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#CV-2x3-123

opening elements shall be within the wall face or slab profile (not misused as arbitrary cuttings)
number
#CV-06-123
based on
IFC2x2, IFC2x3
effects
extended coordination view
date
05. May 2006 - modified 26. Feb 2008
initiator
ISG meeting Munich - modified at ISG meeting Prague 2008
summary opening elements shall be within the wall face or slab profile (not misused as arbitrary cuttings)

 

Description

The IfcOpeningElement is used to denote a semantic object being either an opening or a recess. it should not be used in a general sense of a subtraction body (such as in a CSG difference operation). Therefore the IfcOpeningElement should not be used to create arbitrary clippings, cut-out or other features.

 

#CV-2x3-123-1 Example: Illegal use of the IfcOpeningElement for an arbitrary clipping of the body of an IfcWallStandardCase

The following agreement is made:

  • The IfcOpeningElement shall only be used for true openings and recesses created for a particular design intent.
  • Geometrically the IfcOpeningElement is constraint to be within the body of the voided element, with the exception that the extrusion thickness may extend the thickness of the voided element (see also agreement #CV-06-122).

 

For all other clippings, cut-outs, etc. the RepresentationType 'Clipping' using (subtype of) IfcHalfSpaceSolid, or 'Brep', or 'CSG' should be used.

Note: see #CV-2x3-112 for agreements on support for 'CSG' on export and import.